Range Of Head Motion Research Articles

Evaluation of Apparatus and Protocols to Measure Human Passive Neck Stiffness and Range of Motion

Understanding of human neck stiffness and range of motion (ROM) with minimal neck muscle activation (“passive”) is important for clinical and bioengineering applications. The aim of this study was to develop, implement, and evaluate the reliability of methods for assessing passive-lying stiffness and ROM, in six head-neck rotation directions. Six participants completed two assessment sessions. To perform passive-lying tests, the participant’s head and torso were strapped to a bending (flexion, extension, lateral bending) or a rotation (axial rotation) apparatus, and clinical bed, respectively. The head and neck were manually rotated by the researcher to the participant’s maximum ROM, to assess passive-lying stiffness. Participant-initiated (“active”) head ROM was also assessed in the apparatus, and seated. Various measures of apparatus functionality were assessed. ROM was similar for all assessment configurations in each motion direction except flexion. In each direction, passive stiffness generally increased throughout neck rotation. Within-session reliability for stiffness (ICC > 0.656) and ROM (ICC > 0.872) was acceptable, but between-session reliability was low for some motion directions, probably due to intrinsic participant factors, participant-apparatus interaction, and the relatively low participant number. Moment-angle corridors from both assessment sessions were similar, suggesting that with greater sample size, these methods may be suitable for estimating population-level corridors.

Agreement between a 3D camera system and an inertial measurement unit for assessing the range of motion, head repositioning accuracy and quality of movement during neck and head movements

Purpose : Altered head range of motion (RoM) and head repositioning accuracy (HRA) are commonly reported in neck pain. However, the quality of motion (QoM) is currently not easy to assess clinically. This study investigated the agreement of head rotation recordings using a 3D camera system compared to a commercially available inertial measurement unit (MOTI). Materials and methods : Thirty participants, mean age 26.5 years old (SD 4.4), partook in this study. Participants wore a Headband with MOTI and markers for 3D motion capture analysis during head rotations. The two systems recorded active head RoM in rotation, HRA, and QoM. Agreement of RoM, HRA and QoM data was compared between the two systems using Interclass correlation coefficients (ICC; 2.1) and Bland-Altman plots. Results : Good to excellent agreement between the two systems was seen for RoM (ICC: 0.998), HRA (0.75–0.88) and QoM (ICC: 0.911–0.913). The Bland-Altman plots revealed a systemic offset where the MOTI device measured higher values for RoM (mean bias: −0.56 ± 0.65°), HRA (mean bias: 0.48 ± 0.76°) and QoM (mean bias: −16.9 ± 51.6 A.U.). Conclusion : The present study found that the MOTI device can accurately measure RoM, HRA and QoM during head rotation. MOTI may be preferred over a 3D camera system for clinical use.

Cervical spine injury response to direct rear head impact

BackgroundDirect rear head impact can occur during falls, road accidents, or sports accidents. They induce anterior shear, flexion and compression loads suspected to cause flexion-distraction injuries at the cervical spine. However, post-mortem human subject experiments mostly focus on sled impacts and not direct head impacts. MethodsSix male cadavers were subjected to a direct rear head impact of 3.5 to 5.5 m/s with a 40 kg impactor. The subjects were equipped with accelerometers at the forehead, mouth and sternum. High-speed cameras and stereography were used to track head displacements. Head range of motion in flexion-extension was measured before and after impact for four cadavers. The injuries were assessed from CT scan images and dissection. FindingsMaximum head rotation was between 43 degrees and 78 degrees, maximum cranial-caudal displacement between −12 mm and − 196 mm, and antero-posterior displacement between 90 mm and 139 mm during the impact. Four subjects had flexion-distraction injuries. Anterior vertebral osteophyte identification showed that fractures occurred at adjacent levels of osteophytic bridges. The other two subjects had no anterior osteophytes and suffered from C2 fracture, and one subject also had a C1-C2 subluxation. C6-C7 was the most frequently injured spinal level. InterpretationAnterior vertebral osteophytes appear to influence the type and position of injuries. Osteophytes would seem to provide stability in flexion for the osteoarthritic cervical spine, but to also lead to stress concentration in levels adjacent to the osteophytes. Clinical management of patients presenting with osteophytes fracture should include neck immobilization and careful follow-up to ensure bone healing.

Improvement of head and neck range of motion induced by chronic pallidal deep brain stimulation for cervical dystonia.

Deep brain stimulation (DBS) of the globus pallidus internus (GPi) has become an accepted treatment for severe cervical dystonia (CD). Assessment of therapeutic efficacy of DBS mostly focused on head position at rest but hardly on limitations of head and neck mobility, which represent a functionally important impairment in CD. We aimed to determine prospectively head and neck range of motion (ROM) preoperatively and during chronic bilateral GPi DBS in a series of 11 patients with idiopathic CD or segmental dystonia with prominent CD using a computerized motion analysis. Maximum horizontal rotation of the head in the transverse plane and lateral inclination in the frontal plane were measured preoperatively and at a median of 7months of chronic GPi DBS, using an ultrasound-based three-dimensional measuring system combined with surface electromyography of cervical muscles. Horizontal rotation of the head increased from 78.8° ± 31.5° (mean ± SD) preoperatively to 100.7° ± 24.7° with GPi DBS (p < 0.01), thereby improvement of head rotation to the anti-dystonic side (+ 14,2° ± 12,2°) was greater than to the pro-dystonic side (+ 7,8° ± 9,2°; p < 0.05). Movement-related agonistic-antagonistic EMG modulation during head rotation was enhanced with GPi DBS in both sternocleidomastoid (modulation index (MI) 35.8% ± 26.7% preoperatively vs. 67.3% ± 16.9% with GPi DBS, p < 0.01), and splenius capitis muscles (MI 1.9% ± 24.5% preoperatively vs. 44.8% ± 11.6% with GPi DBS, p < 0.01). Chronic bilateral GPi DBS significantly improves head ROM in CD, likely due to enhanced agonist-antagonist EMG activity with reduced co-contraction. Computerized motion analysis provides an objective measurement to assess the improvement of head and neck mobility in CD.

Validation of an Inertial Sensor Algorithm to Quantify Head and Trunk Movement in Healthy Young Adults and Individuals with Mild Traumatic Brain Injury.

Wearable inertial measurement units (IMUs) may provide useful, objective information to clinicians interested in quantifying head movements as patients’ progress through vestibular rehabilitation. The purpose of this study was to validate an IMU-based algorithm against criterion data (motion capture) to estimate average head and trunk range of motion (ROM) and average peak velocity. Ten participants completed two trials of standing and walking tasks while moving the head with and without moving the trunk. Validity was assessed using a combination of Intra-class Correlation Coefficients (ICC), root mean square error (RMSE), and percent error. Bland-Altman plots were used to assess bias. Excellent agreement was found between the IMU and criterion data for head ROM and peak rotational velocity (average ICC > 0.9). The trunk showed good agreement for most conditions (average ICC > 0.8). Average RMSE for both ROM (head = 2.64°; trunk = 2.48°) and peak rotational velocity (head = 11.76 °/s; trunk = 7.37 °/s) was low. The average percent error was below 5% for head and trunk ROM and peak rotational velocity. No clear pattern of bias was found for any measure across conditions. Findings suggest IMUs may provide a promising solution for estimating head and trunk movement, and a practical solution for tracking progression throughout rehabilitation or home exercise monitoring.

Intervertebral kinematics of the cervical spine before, during, and after high-velocity low-amplitude manipulation

Background contextNeck pain is one of the most commonly reported symptoms in primary care settings, and a major contributor to health-care costs. Cervical manipulation is a common and clinically effective intervention for neck pain. However, the in vivo biomechanics of manipulation are unknown due to previous challenges with accurately measuring intervertebral kinematics in vivo during the manipulation. PurposeThe objectives were to characterize manual forces and facet joint gapping during cervical spine manipulation and to assess changes in clinical and functional outcomes after manipulation. It was hypothesized that patient-reported pain would decrease and intervertebral range of motion (ROM) would increase after manipulation. Study design/settingLaboratory-based prospective observational study. Patient sample: 12 patients with acute mechanical neck pain (4 men and 8 women; average age 40 ± 15 years). Outcome measuresAmount and rate of cervical facet joint gapping during manipulation, amount and rate of force applied during manipulation, change in active intervertebral ROM from before to after manipulation, and numeric pain rating scale (NPRS) to measure change in pain after manipulation. MethodsInitially, all participants completed a NPRS (0–10). Participants then performed full ROM flexion-extension, rotation, and lateral bending while seated within a custom biplane radiography system. Synchronized biplane radiographs were collected at 30 images/s for 3 seconds during each movement trial. Next, synchronized, 2.0-milliseconds duration pulsed biplane radiographs were collected at 160 images/s for 0.8 seconds during the manipulation. The manipulation was performed by a licensed chiropractor using an articular pillar push technique. For the final five participants, two pressure sensors placed on the thumb of the chiropractor (Novel pliance system) recorded pressure at 160 Hz. After manipulation, all participants repeated the full ROM movement testing and once again completed the NPRS. A validated volumetric model-based tracking process that matched subject-specific bone models (from computed tomography) to the biplane radiographs was used to track bone motion with submillimeter accuracy. Facet joint gapping was calculated as the average distance between adjacent articular facet surfaces. Pre- to postmanipulation changes were assessed using the Wilcoxon signed-rank test. ResultsThe facet gap increased 0.9 ± 0.40 mm during manipulation. The average rate of facet gapping was 6.2 ± 3.9 mm/s. The peak force and rate of force application during manipulation were 65 ± 4 N and 440 ± 58 N/s. Pain score improved from 3.7 ± 1.2 before manipulation to 2.0 ± 1.4 after manipulation (p <. 001). Intervertebral ROM increased after manipulation by 1.2° (p = .006), 2.1° (p = .01), and 3.9° (p = .003) at the C4/C5, C5/C6, and C6/C7 motion segments, respectively, during flexion-extension; by 1.5° (p = .028), 1.9° (p = .005), and 1.3° (p = .050) at the C3/C4, C4/C5, and C5/C6 motion segments, respectively, during rotation; and by 1.3° (p = .034) and 1.1° (p = .050) at the C4/C5 and C5/C6 motion segments, respectively, during lateral bending. Global head ROM relative to the torso increased after manipulation by 8º (p = .023), 10º (p = .002), and 13º (p = .019) during lateral bending, axial rotation and flexion-extension, respectively, after manipulation. ConclusionsThis study is the first to measure facet gapping during cervical manipulation on live humans. The results demonstrate that target and adjacent motion segments undergo facet joint gapping during manipulation and that intervertebral ROM is increased in all three planes of motion after manipulation. The results suggest that clinical and functional improvement after manipulation may occur as a result of small increases in intervertebral ROM across multiple motion segments. This study demonstrates the feasibility of characterizing in real time the manual inputs and biological responses that comprise cervical manipulation, including clinician-applied force, facet gapping, and increased intervertebral ROM. This provides a basis for future clinical trials to identify the mechanisms behind manipulation and to optimize the mechanical factors that reliably and sufficiently impact the key mechanisms behind manipulation.

A Comparison of Head-Hand Coordination Patterns during Squash Forehand Strokes in Expert and Less-Skilled Squash Players

Objective: To compare head and hand movement patterns during squash forehand motions between experts and less-skilled squash players. Method: Four experts and four less-skilled squash players participated in this study. They performed squash forehand swings and a VICON motion analysis system was used to obtain displacement and velocity data of the head and right hand during the movement. Mann-Whitney U-tests were performed to compare head and hand range of motion and peak velocity, and cross-correlation was performed to analyze the head-hand coordination pattern between groups in three movement directions. Results: In terms of head and hand kinematic data, experts had greater head range of motion during down swings than less-skilled squash players. Experts seemed to reach peak hand velocity at impact by reaching peak head velocity followed by hand peak velocity within a given temporal sequence. In terms of headhand coordination patterns, both groups revealed high positive correlations in the medial-lateral direction, indicating a dominant allocentric coordination pattern. However, experts had uncoupled coordination patterns in the vertical direction and less-skilled squash players had high positive correlations. These results indicate that the head-hand movement pattern likely an important factor squash forehand movement. Conclusion: Analysis of head and hand movement patterns could be a key variable in squash training to reach expert-level performance.

Use of a Remote Eye-Tracker for the Analysis of Gaze during Treadmill Walking and Visual Stimuli Exposition.

The knowledge of the visual strategies adopted while walking in cognitively engaging environments is extremely valuable. Analyzing gaze when a treadmill and a virtual reality environment are used as motor rehabilitation tools is therefore critical. Being completely unobtrusive, remote eye-trackers are the most appropriate way to measure the point of gaze. Still, the point of gaze measurements are affected by experimental conditions such as head range of motion and visual stimuli. This study assesses the usability limits and measurement reliability of a remote eye-tracker during treadmill walking while visual stimuli are projected. During treadmill walking, the head remained within the remote eye-tracker workspace. Generally, the quality of the point of gaze measurements declined as the distance from the remote eye-tracker increased and data loss occurred for large gaze angles. The stimulus location (a dot-target) did not influence the point of gaze accuracy, precision, and trackability during both standing and walking. Similar results were obtained when the dot-target was replaced by a static or moving 2D target and “region of interest” analysis was applied. These findings foster the feasibility of the use of a remote eye-tracker for the analysis of gaze during treadmill walking in virtual reality environments.

The envelope of motion of the cervical spine and its influence on the maximum torque generating capability of the neck muscles

The posture of the head and neck is critical for predicting and assessing the risk of injury during high accelerations, such as those arising during motor accidents or in collision sports. Current knowledge suggests that the head's range-of-motion (ROM) and the torque-generating capability of neck muscles are both dependent and affected by head posture. A deeper understanding of the relationship between head posture, ROM and maximum torque-generating capability of neck muscles may help assess the risk of injury and develop means to reduce such risks. The aim of this study was to use a previously-validated device, known as Neck Flexibility Tester, to quantify the effects of head's posture on the available ROM and torque-generating capability of neck muscles.Ten young asymptomatic volunteers were enrolled in the study. The tri-axial orientation of the subjects' head was controlled via the Neck Flexibility Tester device. The head ROM was measured for each flexed, extended, axially rotated, and laterally bent head's orientation and compared to that in unconstrained neutral posture. Similarly, the torque applied about the three anatomical axes during Isometric Maximum Voluntary Contraction (IMVC) of the neck muscles was measured in six head's postures and compared to that in fully-constrained neutral posture.The further from neutral the neck posture was the larger the decrease in ROM and IMVC. Head extension and combined two-plane rotations postures, such as extension with lateral bending, produced the largest decreases in ROM and IMVC, thus suggesting that these postures pose the highest potential risk for injury.

Tracking gaze while walking on a treadmill: spatial accuracy and limits of use of a stationary remote eye-tracker.

Inaccurate visual sampling and foot placement may lead to unsafe walking. Virtual environments, challenging obstacle negotiation, may be used to investigate the relationship between the point of gaze and stepping accuracy. A measurement of the point of gaze during walking can be obtained using a remote eye-tracker. The assessment of its performance and limits of applicability is essential to define the areas of interest in a virtual environment and to collect information for the analysis of the visual strategy. The current study aims at characterizing a gaze eye-tracker in static and dynamic conditions. Three different conditions were analyzed: a) looking at a single stimulus during selected head movements b) looking at multiple stimuli distributed on the screen from different distances, c) looking at multiple stimuli distributed on the screen while walking. The eye-tracker was able to measure the point of gaze during the head motion along medio-lateral and vertical directions consistently with the device specifications, while the tracking during the head motion along the anterior-posterior direction resulted to be lower than the device specifications. During head rotation around the vertical direction, the error of the point of gaze was lower than 23 mm. The best accuracy (10 mm) was achieved, consistently to the device specifications, in the static condition performed at 650 mm from the eye-tracker, while point of gaze data were lost while getting closer to the eye-tracker. In general, the accuracy and precision of the point of gaze did not show to be related to the stimulus position. During fast walking (1.1 m/s), the eye-tracker did not lose any data, since the head range of motion was always within the ranges of trackability. The values of accuracy and precision during walking were similar to those resulting from static conditions. These values will be considered in the definition of the size and shape of the areas of interest in the virtual environment.

3208 立体視を用いた二輪車用ライディングシミュレータ構築に関する研究(OS9-1 シミュレータシステムの開発,OS9 ビークルシミュレータの開発と応用,オーガナイズド・セッション(OS))

Our study deals with the development and evaluation of motorcycle simulator for understanding rider's control mechanism. For that purpose, we have been putting much effort for spherical screen visual system, since the effect to the rider's subject evaluation is shown in previous study. Adding to spherical screen, we made it clear that solid angle from rider's eyes should be wider enough to cover eyesight along the rider's range of head motion. To verify this, rider's subjective evaluations are analyzed by our proposal methodology. The quantitative results show usefulness for riding simulator design study.

Head eye co-ordination and gaze stability in subjects with persistent whiplash associated disorders

Symptoms of dizziness, unsteadiness and visual disturbances are frequent complaints in persons with persistent whiplash associated disorders. This study investigated eye, head co-ordination and gaze stability in subjects with persistent whiplash (n = 20) and asymptomatic controls (n = 20). Wireless motion sensors and electro-oculography were used to measure: head rotation during unconstrained head movement, head rotation during gaze stability and sequential head and eye movements. Ten control subjects participated in a repeatability study (two occasions one week apart).Between-day repeatability was acceptable (ICC > 0.6) for most measures. The whiplash group had significantly less maximal eye angle to the left, range of head movement during the gaze stability task and decreased velocity of head movement in head eye co-ordination and gaze stability tasks compared to the control group (p < 0.01). There were significant correlations (r > 0.55) between both unrestrained neck movement and neck pain and head movement and velocity in the whiplash group. Deficits in gaze stability and head eye co-ordination may be related to disturbed reflex activity associated with decreased head range of motion and/or neck pain. Further research is required to explore the mechanisms behind these deficits, the nature of changes over time and the tests’ ability to measure change in response to rehabilitation.

Techniques for field application of lingual ultrasound imaging

Techniques are discussed for using ultrasound for lingual imaging in field‐related applications. The greatest challenges we have faced distinguishing the field setting from the laboratory setting are the lack of controlled head/transducer movement, and the related issue of tissue compression. Two experiments are reported. First, a pilot study identifies important factors in controlling head/transducer movement in field settings. Second, an Optotrak/ultrasound study reports the range of head movement in an optimal field‐like setting within and across varying phonetic contexts, as well as the effect of tongue tissue compression on tongue image data. Results suggest that with a simple arrangement involving a head rest or surface, a fixed transducer, and careful design and presentation of stimuli, reliable lingual ultrasound data can be collected in the field.

Quantifying Head Motion Associated with Motor Tasks Used in fMRI

In functional magnetic resonance imaging (fMRI) studies, long experiment times and small intensity changes associated with brain activation frequently lead to image artifacts due to head motion. Methods to minimize and correct for head motion by restraint, fast imaging, and retrospective image registration are typically combined but do not completely solve the problem, particularly for specific patient populations. As an initial step toward optimizing future designs of head restraints and improving motion correction techniques, the head motion characteristics of groups of stroke subjects, age-matched controls, and young adults were investigated with the aid of an MR simulator and a highly accurate position tracking system. Position measurements were recorded during motor tasks involving either the hand or the foot. Head motion was strongly dependent on the subject group and less upon the task conditions based on ANOVA calculations (P < 0.05). The stroke subjects exhibited approximately twice the head motion compared to that of age-matched controls, and the latter's head motion was about twice that of young adults. Moreover, the range of head motion in stroke subjects over all tasks was approximately 2 ± 1 mm, with the motion occurring predominantly as translation in the superior–inferior direction and pitch rotation (nodding). These results lead to several recommendations on the design of fMRI motor experiments and suggest that improved motion correction strategies are required to examine such patient populations comprehensively.

Analysis of Static and Kinetic Abnormalities Typical of Torticollis, and Postoperative Changes

The clinical pattern of torticollis and surgical results were evaluated. Head posture and range of motion were measured. The authors use a newly designed device consisting of an orthogonal system to which head position is referred. Preliminary data were obtained on 24 patients with torticollis and 21 healthy control subjects. The examination of posture shows that the head usually twists in opposite directions simultaneously around a vertical and a sagittal axis, and the deflection is greater in one direction. Head position affect body posture, with the trunk often compensating for head deviation. Although there are almost always abnormalities on EMG recordings of neck muscles, these do not indicate the degree and pattern of deformity. Because of the disorder of muscle innervation, head movements are affected, with an asymmetrical decrease in the range of motion in comparison with normals (p < 0.05). Movements are greater toward the direction of postural deviation. Eleven patients were studied before and after undergoing a bilateral C1-C3 rhizotomy and selective section of the XIth rootlets, which carry motor fibers to the sternocleidomastoid muscle. Head posture immediately improved (p < 0.05), with better appearance, despite some residual distortion (less than 10%), and trunk alignment also improved . In contrast to posture, head range of motion was worse than before (p < 0.05). The most improved movement was rotation, followed by flexion/extension. Further improvements were observed at later follow-up. Surprisingly, the range of motion gradually increased, surpassing preoperative limits (p < 0.05). Our study documents the usefulness of surgery in correcting torticollis. Posture is immediately affected; motion increases despite denervation, after an initial decline.

Electrotherapy and hyperbaric oxygen: Promising treatments for postradiation complications

Electrotherapy and hyperbaric oxygen therapy have been added to physical therapy to treat patients with postsurgery and radiation sequelae. Problems of reduced oral opening and range of head movement, soft tissue necrosis, osteoradionecrosis, and delayed wound healing were addressed in 37 patients over a 3-year period. of this group, 16 irradiated maxillary resection patients were specifically followed up to determine the effectiveness of the new modalities on improving reduced oral opening. Although healing and the quality of the soft tissues showed marked improvement there was no significant improvement in oral opening.

An Evaluation of the Need of the Long-Stay Psychiatric Patient for Organised Exercise

Nine long-stay psychiatric patients, known to have had little organised exercise for some years, were involved in a programme of group physical activity for fourteen weeks following tests for body mobility as typified by range of head movement, length of stride and ability to raise the arms above the head. Positive physical gains were demonstrated relative to a non-exercising control group when tests were repeated at the end of the programme, and greatest benefit appeared to be derived by patients whose diagnosis included a degree of retardation or dementia. Every test subject exhibited some improvement in social behaviour, at least whilst in the group situation.